1. Field of the Invention
The present invention, generally, relates to ribbon re-inking devices and, more particularly, to a new and improved mechanism by which ink is transferred from an ink reservoir for replenishing the ribbon under a measure of control.
Usually, today, a supply of ink in a pad of porous material is maintained in close contact with a ribbon in a wiping or a rolling action under substantially constant pressure to replenish the ink as the ribbon is used. It is the custom to form such porous material as a circular roller and to mount it within the ribbon cartridge where it is maintained in contact with the ribbon, thereby extending the operating life of the ribbon.
2. Description of the Prior Art
One practice that has found favor in the art today uses a second roller intermediate the porous ink-filled roller, and this roller is called a"transfer" roller.
The ribbon is wrapped part way around the peripheral surface of the transfer roller with the re-inking roller in contact with a different part of the periphery of the transfer roller. Actually, the transfer roller and the re-inking roller are supported rotatably on their own shafts.
Since the re-inking roller and the transfer roller are in contact with each other, as one turns, so turns the other. Thus, as the ribbon is moved by the apparatus using it, this action provides the motive power for turning both the transfer roller and the re-inking roller. Whether such a ribbon is used in a typing apparatus or in an impact printer apparatus, it is the practice today to provide some form of ink replenishing supply.
In impact printer apparatus, it is current practice to augment the supply of ink in the ribbon. This additional ink is contained in a reservoir formed of porous, sponge-like material in the shape of a circular roller, and the transfer roller is located between the ribbon and this ink supply roller.
It is also current practice for such impact printers to enclose both the ribbon and the re-inking mechanism in a cartridge. These cartridges, however, have not been a panacea in extending the operating life of the ribbon, because they have had their own problems.
The patented prior art describes several arrangements for re-inking devices. For example, U.S. Pat. No. 2,770,215 to Knight describes an early form of a device for furnishing ink continuously to an inked ribbon.
U.S. Pat. No. 4,536,098 to Sheehan et al. describes a ribbon cartridge with a re-inking mechanism to extend the life of the ribbon.
U.S. Pat. No. 4,913,571 to Bulson et al. describes a ribbon cartridge with a re-inking roller and transfer roller assembly arranged to prevent a failure due to a long period of non-use. This patent is assigned to the Assignee of the present invention.
While the structural arrangements of these prior devices, at first appearance, have similarities with the present invention, they differ in material respects. These differences, which will be described in more detail presently, are important for the effective use of the invention to achieve its advantages.